This invention relates to gaseous fuel systems for engines and, in particular, to a system suitable for use in bi-fuel engines as well as in other engines.
It is known in the art relating to bi-fuel engines for vehicles to provide independent gasoline and gaseous fuel (gas) injection systems for alternatively operating the vehicle on either gasoline or gas as a fuel. Systems using liquefied petroleum gas (LPG) in gaseous form or compressed natural gas (CNG) are currently of interest. Such bi-fuel systems offer the environmental benefits of low emission technology without the refueling limitations and short driving range of dedicated fuel vehicles.
A factor in the cost of such vehicle systems is the cost of modifying the well developed gasoline fuel system of a current vehicle engine to accept the gas fuel system. Engine modifications that change the relationship of the gasoline fuel injectors with the air induction system could not only increase the assembly and development costs but could require additional testing for both emission regulation compliance and fuel system collision integrity. Such modifications may include alteration of cylinder heads, manifolds and/or combustion chamber configurations to accommodate gas fuel injectors in addition to the gasoline fuel injectors.
The present invention provides a gas fuel injection system that may be added to an engine having a proven gasoline fuel injection system with a minimum of modifications and a limited requirement for further development and testing.
The gas fuel system includes an injector block that connects with the outlet ends of gas fuel injectors. An inlet header may be included that connects with the inlet ends of the injectors to form an injector block assembly that may be located in a sheltered vehicle location away from the forward portion of the engine in the vehicle. The gas injectors sequentially admit pressurized gas to gas distribution lines connecting with the engine intake ports. Preferably, the distribution lines connect with gas distributors of any suitable type located in intake port openings of an adapter. The adapter is preferably formed as a plate that is fitted between the engine cylinder head, or other intake port defining body, and an associated intake manifold with the intake port openings of the adapter aligned with the engine intake ports.
The inlet header of the system defines a plenum connected with a pressurized gas fuel supply including a pressure regulator and a gas shutoff valve. The fuel supply delivers gas in gaseous form through the shutoff valve and the pressure regulator to the inlet header of the injector block assembly from which the individual injectors are fed. The injectors may be any type of gas injector suitable for engine intake port injection. The inlet header and injector block are made to sealingly connect with the particular injectors selected and the header and block are connected by suitable supports such as struts or rods to hold the injector block assembly together as a unit and maintain the injectors in place in the assembly.